Slot Detection of PXI Modules, More details

[John_Sch.]

I read the knowledge base titled: Slot Detection of PXI Modules but have a few questions about it. How often to I have to do this? When I insert or remove a board from the PXI chassis? When I insert or remove an additional chassis in daisy chain? With Multiple chassis in Daisy chain. How do I know which device number is which card? ie if I have 2 of the same model of cards both in slot 5 but in different chassis. If I remove a card, am I guarranted that other cards device numbers will not change?

[Claudia]

John,

The Knowledge Base (KB) "Slot Detection of PXI Modules" says that the PXI Initialization File (PXISYS.INI) file must be saved in the systems directory in order for the system to be able to identify the slot where a board is located. This is because every slot in a PCI Bus (a PXI system uses a PCI bus) has a PCI Device Number and PCI Bus Number associated with it. The PXISYS.INI file describes the architecture of the chassis and the controller, and has the appropiate PCI Device Number and PCI Bus Number for every slot. There is a unique PXISYS.INI file for every combination of PXI chassis and PXI controller.

How often to I have to do this? When I insert or remove a board from the PXI chassis?
Currently you do not need to edit the PXISYS.INI file. You can download the PXISYS.INI file from our website and use it as it is (see link in the KB you were reading). So you only need to save once the appropiate PXISYS.INI file to the Windows Systems directory, regardless of whether you change the PXI board in your system.

When I insert or remove an additional chassis in daisy chain? With Multiple chassis in Daisy chain?
If you are daysi-chaining chassis, keep in mind that the current PXI Standard DOES NOT support daysi-chaining. However, in previous PXI configurations, I have successfully edited a PXISYS.INI file so I can do Slot Identification in daysi-chained chassis (not in star configuration, though). The steps I followed are in the text file attach to this e-mail.

How do I know which device number is which card? ie if I have 2 of the same model of cards both in slot 5 but in different chassis. If I remove a card, am I guarranted that other cards device numbers will not change?
Finally, if you are using NI DAQ boards, NI-DAQ driver will assign a Device Number to the boards that correspond to the Slot Number, and the Slot Number is described in the PXISYS.INI file that you edited following the instructions in the text file attached below.
If your boards do not use the NI-DAQ driver, but support NI-VISA, you can use the PXI VISA Instrument Descriptor to find out the Slot they are installed in. See the KB "Programmatic Slot ID" linked below for more information. It has an Example Program linked to it too:

KnowledgeBase 2MDFG2WD - Programmatic PXI Slot Detection


Let me know if I can be of further assistance,

Claudia Lorente
Applications Engineer
National Instruments
http://www.ni.com/